Here  are  the  codes for the Tricky, Taxing and Mayhem levels of
the original Lemmings. The tame level is just far too, er, tame:

Tricky:

1  LCANLMFPDK    16 LMBIJNOOEY
2  CIOLMFLQDU    17 ICANLMLPEO
3  CAJJLDMBEV    18 CINLMDMQET
4  MKJNLICCEJ    19 CAKHNNIBFN
5  OHNDICEDEM    20 IJJLFMCCFR
6  JLDMBMNEEX    21 NHLFMCEDFO
7  LDMCAJNFEN    22 JNNICMNEFR
8  DMCMJLLGEY    23 LFMCEJLFFS
9  MCANLLDHER    24 NMBIJNNGFS
10 CMNLLDMIEO    25 MCENLLFHFY
11 CAJJOLIJEU    26 BINNNFIIFM
12 IJHMDMCKEV    27 CAJJMFMJFR
13 OHMLICALEX    28 MKJONICKFV
14 JMLICMOMEW    29 NJONICELFR
15 MDMCEJLNEY    30 JMFMCINMFQ

Taxing:

1  MFMCAJNNFJ    16 HMDHFINMGL
2  FKBIJLMOFN    17 ODHFAKNNGJ
3  IBANLMFPFY    18 LHGMKNOOG
4  BINLMFIQFR    19 LGENLMDPGT
5  FAJHLDHBGT    20 GINNOLHQGQ
6  IJHLDHFCGM    21 GEKJNNHBHY
7  NHLDHFADGJ    22 IJJLFLHCHW
8  HLDHFINEGS    23 NHNNHGADHX
9  LDHFAJLFGL    24 JNNHGMOEHX
10 DLFMKLLGGN    25 LFLGAKLFHU
11 HFANLLDHGR    26 NHGIJNNGHU
12 FINLLDHIGK    27 LGAOLLFHHX
13 GAKHOLHJGY    28 GINLNNHIHY
14 MJHMDHFKGJ    29 GEKJMFHJHX
15 NHMDHFALGS    30 MKJONHGKHK

Mayhem:

1  NJMFLGALHM    16 IJHMDIFRIY
2  KONJGMOMHT    17 NJMDMGALIM
3  OOHGCKNNHY    18 HMDIFINMIO
4  GLGIJNMOHY    19 MDIFEJLNIL
5  NGANOMFPHX    20 DIFIJLMOIQ
6  GINOMFLQHO    21 MGAOLMDPIT
7  GAJJLDMBIN    22 GINLMDMQIL
8  KJHLDMGCIW    23 GAKHLFMBJP
9  OHLDMGCDIU    24 IJHLFIFCJS
10 HLDMGMOEIP    25 NHLFIFADJP
11 LLIGEJNFIN    26 HLFIFINEJY
12 LIFIKLLGIQ    27 LFIFAJLFJR
13 IFANLLDHIU    28 FIFIJLLGJK
14 FINLLDIIIN    29 IFANLLFHJX
15 FAJHMDIJIP    30 FINLLFIIJQ